package ljl.alg.wangzheng_camp.round1.recursive;

public class _offer_10_2_frog_jump_stairs {
    
    /**
     * 脑子一热，写错了...
     * */
    public int numWays(int n) {
        int a = 1, b = 1;
        while (n-- > 0) {
            int t = a;
            a = b;
            b = (b + t) % 1000000007;
        }
        return a;
    }
}
